An Aug. 5 study in Nature Neuroscience shows the first physical evidence that humans have "grid" cells, which are so named because neurons have a grid pattern. The cells work with other cells in the brain to help us remember our location and how far we have traveled.

The brain neurons have been confirmed in a few other species, including monkeys and rats. They form triangular formations that, working in tandem with "place" and "direction" cells, help the brain do "path integration" -- laying down navigation markers at every turn a person takes while traveling.

Without grid cells, it is likely that humans would frequently get lost or have to navigate based only on landmarks. Grid cells are thus critical for maintaining a sense of location in an environment.
- Joshua Jacobs, study coauthor, Drexel University

Researchers had previously theorized that humans had grid cells, but the study helped identify the cells. The researchers were able to do so by working with epilepsy patients who, as part of their treatment, had electrodes placed deep into their brains.

Added August 6, 2013 at 3:07 a.m.

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Scientists Find Evidence Of Brain's Grid Cells That Help Us Navigate: Are Men Better At Finding Their Way?

Researchers had 14 patients play a video game where they rode a bicycle through open terrain while trying to remember and recall locations. Using the electrodes, researchers observed grid cells in action. The cells activated at certain times depending on where in the virtual game the patients were.

May-Britt Moser, Edvard Moser and John O'Keefe won the Nobel Prize for Physiology or Medicine Oct. 6 "for their discoveries of cells that constitute a positioning system in the brain." The system, described as an "inner GPS," includes "place cells" and "grid cells" for animals to navigate in space.